[TowerTalk] Coax Grounding on a tower.

K8RI on Tower talk k8ri-tower at charter.net
Tue Jun 27 05:10:55 EDT 2006

> Roger,
> Here's a couple pictures of the bulkhead assembly I made for the top of my
> tower...
> http://tinyurl.com/rc9v2   See photo's D, E, and F.

Your feed through bracket is *almost* identical to mine with the only real 
difference being the mounting of the bracket.  Mine mounts to the tower legs 
so the U-bolts are horizontal and have an insert like a boom to mast clamp 
so the angle is in contact with the tower leg for about a third of the 
distance around the leg.

> At HF there's negligible insertion loss through a couple extra connectors.
> BTW, I'm done fighting the PL-259 soldering issues and going with crimp-on
> connectors for my Belden 9913 cable. I just ordered a couple dozen from

I've been using two different types of crimp on for the TV stuff and they 
are strong enough to hold my weight compared to the regular crip on that you 
can pull off with two fingers.  So, with that experience I'm thinking quite 
seriously of going to crimp ons for the big stuff as well.  As far as 
weather proofing I use the flooded heat shrink which works well and is easy 
to install.  DX engineering had 1000 foot spools of flooded RG-6 very 
reasonable.  Good stuff and far cheaper than I can get it around here.

> Tessco along with the proper die for my crimper. I'll see how these work

I think I'm going to order about a dozen or so of those and a crimper to 
give them a try.  Soldering while standing on the top plate at 100 feet is a 
bit inconvenient.  Who's a good source price comparrison wise?

> over the long run. I never was a crimp fan until I started working with
> computer network cables and saw how secure the connections really were.
I noted the QST article where the guy wired things up with Cat5e, but all of 
his connections are pin for pin. That's fine in the wall but one of the 
connecting cables either into the wall or out of the wall has to have some 
wires swapped. I didn't see any of that mentioned in the article.


Roger Halstead (K8RI and ARRL 40 year Life Member)
N833R - World's oldest Debonair CD-2

> Also, I run my cables down the inside of the south legs to gain some
> shielding from the high-noon sun.
> 73 de Bob - K0RC
> ------------------------------
> Message: 5
> Date: Mon, 26 Jun 2006 22:02:13 -0400
> From: "K8RI on Tower talk" <k8ri-tower at charter.net>
> Subject: [TowerTalk] Coax Grounding on a tower.
> To: <TOWERTALK at contesting.com>
> Message-ID: <008301c6998d$b62e8ba0$6400a8c0 at SecondOne>
> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
> reply-type=original
> Due to basement work I've had to pull all the cables out of the conduit.
> Man, but I was sore the other day and was wondering whey until I realized
> I'd pulled between 1300 and 1500 feet of cable out of conduit the previous
> evening.
> This has put me off-the-air with the main station which is probably why
> 6-meters has been open the last couple of weeks.
> As this is turning into a rotator repair (It's hanging up again and the
> thrust bearings are free), antenna repair, antenna removal, replace the 
> pig
> tails, and reroute the coax project I've decided that as long as the coax
> has to go through connectors at the end of the pigtails at the top of the
> tower I'm going to mount an aluminum angle across the face of the tower 
> with
> 3" UHF feed throughs.  Each of the current 4 pig-tails will fasten to a 
> feed
> through which will ground the brade to the tower at the top. The cables 
> then
> run down the inside of the NE tower leg where they are joined by two more 
> to
> the base and loop up into the junction box where they enter the 3" conduit
> to the house.  The cables will be jointed by at least one or two more part
> way down the tower, but there may be two less from the top.  The easiest 
> is
> to just say the number may vary.
> My thoughts are to either use another set of bulk head connectors on
> Aluminum angle bracketed to the tower as at the top, or to clamp those
> brackets to the leg of the tower using a hose clamp and spacers so the
> center part of the feed through will be grounded to the tower leg.
> This will add one more set of connectors to the cables but from experience
> and information gleaned from TT I'd say the insertion loss of the one 
> extra
> connector is going to be almost non existent. In addition the cables will 
> be
> grounded to the tower where they are leaving the tower.
> The new junction box at the house entrance will be putting the shield
> grounds and the Polyphasors (sp?) right outside  the house at the point of
> entry where they are currently just inside the house.  I think this will 
> be
> an bit of an added safety feature.
> One leg of the tower ground system will be entering the Hoffman box beside
> the conduit, grounding the back plate inside and then continuing into the
> house with the other cables. This #2 runs directly through to the house
> ground for the electrical service as it's the only way I can get it there.
> I'd have to tear up a rather expensive garage apron to get there outside 
> and
> that would make the grounds different length.
> This is going to get rid of the conduit coming through the basement wall.
> It'll come in through the end plate of the floor joists and there will be 
> no
> cables showing below the basement ceiling.  At least that is the plan.
> Remember it's normal for this installation to take at least three 
> lightning
> hits a year and I think it's already had it three (or more) just in the 
> last
> storm.
> Any socially acceptable suggestions?
> Roger Halstead (K8RI and ARRL 40 year Life Member)
> N833R - World's oldest Debonair CD-2
> www.rogerhalstead.com
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